- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
The sintering behavior and physical properties of Li <sub/>2</sub> CO <sub/>3</sub> -doped Bi <sub/>0.5</sub> (Na <sub/>0.8</sub> K <sub/>0.2</sub> ) <sub/>0.5</sub> TiO <sub/>3</sub> lead-free ceramics
摘要： In this study, Li2CO3-doped Bi0.5(Na0.8K0.2)0.5TiO3 (BNKT) ceramics were fabricated via the conventional solid-state reaction using ultrasound waves for preliminary milling. The milling time was shortened from 20 h to 1 h with ball milling. The phase structure of BNKT investigated by X-ray diffraction showed a single perovskite phase. With increasing Li2CO3 content, the phase structure of the ceramics changed from rhombohedral to tetragonal. At a sintering temperature of 1 100 8C and Li2CO3 content of 0.4 wt.%, the best physical properties of the ceramics, such as density (q), 5.9 g cm–3; electromechanical coupling factors (kp), 0.32; (kt), 0.29; remanent polarization (Pr), 12.0 lC cm–2; dielectric constant (er), 1 191; and highest dielectric constant (emax), 5 800, were obtained.
关键词： Lead-free ceramics,Electromechanical coupling factor,BNKT,Sintering temperature,Dielectric constant
更新于2025-09-23 15:23:52
-
Effects of sintering temperature on the microstructure and luminescence of LuAG:Pr ceramics
摘要： The effects of the sintering temperature on the microstructure and luminescence of Lu3Al5O12:Pr (LuAG:Pr) ceramics was investigated by density, X-ray diffraction (XRD), scanning electron microscopy (SEM), grain size, attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR), photoluminescence (PL), radioluminescence (RL), and thermoluminescence (TL) measurements. A Czochralski-grown single crystal was used as reference. The increase of the sintering temperature promoted progressive structural modifications toward the characteristics of the single crystal. The presence of an amorphous phase was strongly detrimental to the luminescence of LuAG:Pr, with its elimination leading to enhanced RL and reduced TL emission. Evidence of synergism between the F-related defects and the Pr3+ 4f - 4f and 4f - 5d transitions was also found with the presence of these defects being detrimental to the 4f - 5d scintillation.
关键词： ceramics,sintering temperature,luminescence,microstructure,thermoluminescence,Lu3Al5O12:Pr
更新于2025-09-23 15:22:29
-
[IEEE 2019 IEEE 58th Conference on Decision and Control (CDC) - Nice, France (2019.12.11-2019.12.13)] 2019 IEEE 58th Conference on Decision and Control (CDC) - Design and implementation of a backstepping controller for regulating temperature in 3D printers based on selective laser sintering
摘要： In this paper we investigate the preheating temperature control problem in 3D printers based on the selective laser sintering (SLS) technology. We formulate the process as a temporal sequence of diffusion partial differential equations (PDEs), where each of these PDEs represent the temperature distribution of the layers and the control variable appears at one of the boundary conditions. We propose a full-state feedback control law, an state observer and the associated output feedback control law for the boundary input. The associated output feedback controller ensures the exponential stability of the estimation error in the L2 norm. The theoretical results were tested through numerical simulations and experiments. These results are promising as a method for industrial implementation of the backstepping controller.
关键词： 3D printers,backstepping control,selective laser sintering,temperature control,partial differential equations
更新于2025-09-19 17:13:59
-
Effects of sintering temperature on sensing properties of WO <sub/>3</sub> and Ag-WO <sub/>3</sub> electrode for NO <sub/>2</sub> sensor
摘要： Pure WO3 and Ag-WO3 (mixed solid solutions Ag with WO3) have been successfully synthesized by sol-gel method and the influences of calcination temperature on the particle size, morphology of the WO3 and Ag-WO3 nanoparticles were investigated. Powder X-ray diffraction results show that the hexagonal to monoclinic phase transition occurs at calcination temperature varying from 300°C to 500°C. SEM images show that calcination temperature plays an important role in controlling the particle size and morphology of the as-prepared WO3 and Ag-WO3 nanoparticles. The NO2 gas sensing properties of the sensors based on WO3 and Ag-WO3 nanoparticles calcined at different temperatures were investigated and the experimental results exhibit that the gas sensing properties of the Ag-WO3 sensors were superior to those of the pure WO3. Especially, the sensor based on Ag-WO3 calcined at 500°C possessed larger response, better selectivity, faster response/recovery and better longer-term stability to NO2 than the others at relatively low operating temperature (150°C).
关键词： tungsten trioxide,sintering temperature,low operating temperature,gas sensing properties
更新于2025-09-11 14:15:04
-
Modifications in structural, optical and electrical properties of nanocrystalline CdO: role of sintering temperature
摘要： Present report deals with the synthesis of nanocrystalline cadmium oxide (CdO) using low-cost acetate precursor based modified sol–gel technique. Final product was sintered at different temperatures and studied for their structural, optical and electrical properties. In this present work, we report the sintering temperature-dependent structural, optical and electrical properties of nanocrystalline cadmium oxide (CdO) grown by cost effective sol–gel method. Structural properties of CdO materials were investigated by X–ray diffraction (XRD) which reveals the crystalline phase of the samples without any detectable impurity within the range of measurements. Crystallite size (CS), calculated using Scherer’s formula, is found in the range of nanometer (<100 nm) and increases with increasing sintering temperature. Average crystallite size of all CdO nanocrystals were estimated using the William–Hall (W–H) plots from XRD patterns. Furthermore, transmission electron microscopy (TEM) images were captured to check the crystallinity and particle growth of the samples. The optical properties of nanocrystalline CdO were studied by using UV–Visible (UV–Vis) absorption spectrum. High absorption has been observed for nanocrystalline CdO sintered at lower temperatures. The band gap of nanocrystalline CdO was calculated by using Tauc’s law where band gap increases with increasing sintering temperature. The electrical properties of the samples were studied by performing dielectric and AC conductivity measurements. It is observed that dielectric constant decreases with increase in frequency and sintering temperature. Variation in AC conductivity with light and sintering temperature has been discussed in detail.
关键词： Nanocrystalline,Photoconduction,Sol–gel synthesis,Sintering temperature
更新于2025-09-09 09:28:46